The authors, who took part in designing and conducting the first phase-1 clinical trials of the HIV vaccine between 1991 and 1996, discuss the history of this innovative program, in particular, the conditions under which volunteers were recruited. They recall its multidisciplinary aspects; the team included, along with clinicians who were used to performing such trials, epidemiologists, psychiatrists, psychoanalysts, social psychologists, and a philosopher specialized in ethics. When forming this team, officials at France's National Research Agency on AIDS (ANRS) were careful to identify the volunteers social characteristics and pay heed to their subjective motivations for participating, given the context, namely a rising incidence of HIV infection and the challenges that were undermining confidence in medicine. Important in this context was the application of the Huriet-Sérusclat Act (1988) with its provisions for protecting participants. These clinical trials led to reformulating several ethical questions, for instance, the tension between the need of such trials and the necessity to not expose volunteers to poorly known risks; the importance of precise scientific information for delivering free, informed consent; and the possibility for volunteers to take part on the basis of their autonomy and "risk choice." The network of volunteers, which operated on this basis for nearly 25 years, is a rare example of collaboration between basic research in biomedicine, medical doctors, psychologists, psychoanalysts, and ethicists.